Beautiful work! I think a longarm would make your life much easier! It sounds to me as though you have no need of the computerized/robotics so you should be able to find a longarm that has just the channel locks for your horizontal and vertical needs, and a ruler would help you achieve the other line work you need. Longarms come in a wide range of prices with various bells and whistles.
We have some amazing long-armers here that I am sure will chime in with more information. I highly recommend YouTube for videos about longarm’s there are some amazing people who post their tutorials and just videos of them working.